What was going on when I was born?

In the late 1970's, when videotape recorder sales began rising throughout the world, two Japanese companies saw an opening. Where there are recorders, the reasoning went, there will be tapes. And while the Fuji Photo Film Company was probably the first to begin production of videotape cassettes for retail sale, it did not remain the largest producer. The TDK Electronics Corporation, which had been making audio tapes since the early 1950's, quickly eclipsed its rival, assuming a lead it has held ever since. Today, the company is the world's largest producer of videotape cassettes, supplying as much as 35 percent of overall world demand.

The Nets' 110-95 victory over the San Diego Clippers before 14,313 fans at Byrne Meadowlands Arena this afternoon was not a stylish one. It was achieved against a struggling and battered team reminiscent of the Nets before they became playoff contenders. Six Nets scored in double figures, led by Ray Williams's 23 points. New Jersey ran away from the Clippers by outscoring them, 12-3, at the end of the third period for a 76-63 lead.

International El Salvador's election next month is regarded gloomily by President Reagan's senior advisers. They are also doubtful about the ability of the Salvadoran Government to achieve a military victory over the rebels. Administration officials said President Reagan had been receiving increasingly pessimisitic reports that the guerrillas would succeed in reducing participation in the March 28 election by threats and confiscatng voter identification cards at gunpoint. (Page A1, Col. 6.) Central America's problems are being exaggerated by the international press and by some United States politicians, the President of El Salvador's junta, Jose Napoleon Duarte said in an interview. He Duarte said in an interview. He said the international attention is harming the ''little countries,'' including Nicaragua and El Salvador. He also said that if his Christian Democrats win the March 28 elections they will not negotiate with the ''extreme left'' or the ''extreme right'' over a share of the power. (A1:4-5.)

The nation's ailing savings industry is approaching the ultimate crunch, and there are a variety of proposals on to how to deal with it. Figures released last Friday by the New York State Banking Department confirmed the seriousness of the situation. During the fourth quarter, New York City's 34 savings banks alone lost $337 million, with several of the larger banks rapidly running out of reserves. The situation is similar across the country. Some officials are privately predicting that by year-end as many as 600 failing savings banks and savings and loan associations will need assistance from the Federal deposit-insurance agencies.

The Rangers played one of their weaker games of the season last night, losing, 4-2, to the Pittsburgh Penguins at Madison Square Garden. The Rangers started the game poorly when Ed Mio gave Peter Lee, the Penguin forward, three chances to score on the same play. Mio stopped Lee's first shot but could not control the puck, giving Lee two more chances, and he finally poked in a rebound with 3 minutes 1 second gone. The Rangers tied the game on a goal by Mikko Leinonen and outshot the Penguins, 19-8, in the first period. But Mio gave up another goal, to Pat Price, on a rebound in the middle of the second period, and the Rangers never caught up.

Bevis Longstreth, one of three Securities and Exchange commissioners who voted against bringing an enforcement action against Citicorp for inadequate disclosure of its foreign currency trading practices, says he once represented the bank and was a partner until last year in a law firm that has long had Citibank as a client. Mr. Longstreth testified last July at his confirmation hearings that he intended to withdraw from ''any enforcement proceeding in which my former firm was involved in any way in representing a party.'' Mr. Longstreth said in a telephone interview that his Senate pledge was meant to apply only to clients his former firm, Debevoise, Plimpton, Lyons & Gates, represents before the S.E.C., not to general representation as is the case with Citibank. Neither Mr. Longstreth's testimony nor his written submissions to the Senate specifically mention S.E.C. representation as the basis for disqualification.

In the face of increasingly violent juvenile crime, the Family Court in New York City is being misused as a haven for young muggers and marauders, according to interviews with judges, lawyers, court officials and family-law experts. They say the traditional policies of anonymity and leniency given to young offenders in the court have become outmoded. The court's judges, acting in secret with suspects who are not identified because they are under 16 years old, dismiss charges, set youths free and even send those who have been convicted back to parents, foster homes or the streets in overwhelming numbers. Despite changes in the state law in 1978 that made the juvenile provisions the toughest in the country and gave the adult courts authority to handle the most serious juvenile cases, the district attorneys reduce most of the charges, and the judges send the cases back to Family Court. For the cases that remain, the adult court judges rarely impose the stiffer penalties.

The recession has deepened, and the prospect for some visible recovery this spring is disappearing under the weight of persistently high interest rates and bad winter weather, leading economic forecasters now say. While sticking to their forecast of a significant recovery in the second half of this year, some of these private forecasters have nonetheless scaled down this prediction, reflecting the drag imposed because interest rates are declining more slowly than expected. For example, the banks' prime rate, a bellwether rate that affects many others, now stands at 16 1/2 percent. Although this is four percentage points below its high of 20 1/2 percent, reached last June and July, it has risen three-fourths of a point since the beginning of this year. ''The rise in interest rates delayed the recovery at least a quarter,'' said Thomas D. Thomson, chief economist of the Crocker National Bank of San Francisco. In the second half, he predicted, it will be ''more of a bite on the economy'' than previously expected.

Virginia B. Smith, the president of Vassar College, warns that private colleges and universities are losing ground in their effort to maintain social and economic diversity, in part because they were ''seduced'' into becoming too dependent on Federal student aid programs. ''Back in the 60's and early 70's we didn't think very far ahead about the possible consequences of all these programs,'' she said. ''It never occurred to us that someday they might be cut off precipitously.'' Miss Smith was one of two college presidents interviewed recently to gauge the reaction of private colleges and universities to the Reagan Administration's education policies.

WILLIAMSTON, N.C. THE lavender blue telephone rang and Gaylord Perry, the elderly spitball pitcher without a team, picked it up before it had a chance to ring again. Any call now could be the one. It was late morning, and he was sitting at his desk in his home here, having recently come in from performing considerable chores on his peanut farm. He still wore a yellow cap that covered a baldish head, and a plaid shirt, blue jeans and work shoes, which he had washed off with a hose before entering the house. ''Hello,'' he said into the phone. Then, ''Oh, how ya doin', Bob.'' Perry told the caller that he still hadn't found a team to play with this year, but was still working on it, still thought it would happen. ''Uh huh, 20 two-pound bags,'' said Perry, writing down the man's order. ''Right, a picture of me pitching and a tractor and my signature is on the burlap bags. ...

President Reagan's senior advisers say they are not optimistic about the chances of a successful election next month in El Salvador, or about the Salvadoran Government's ability to achieve a military victory over the rebels. But the advisers say they are not sure what the United States should do next to help the authorities in San Salvador. The elections for the Constitutional Assembly, scheduled for March 28, have been regarded by United States officials as crucial to bolstering the Christian Democratic Party, which is headed by Jose Napoleon Duarte, head of the military-civilian junta. But Administration officials said President Reagan had been receiving increasingly pessimistic reports that the guerrillas would succeed in reducing participation in the elections by threats and in some cases by confiscating voter identification cards at gunpoint.

Continental Air Lines, struggling with slipping revenues, costly labor agreements and impatient lenders, is weighing stern measures to relieve the mounting pressure. The company has said it will slash its payroll nearly in half and eliminate dozens of routes if it is unable to persuade its unions to ease work rules, cap wages and prune jobs. With the union talks in their final hours, Continental directors are to meet on Tuesday to decide the future of the nation's 10th-largest airline. ''I don't think labor has much of a choice,'' said Barry Gordon, an analyst at the National Aviation and Technology Corporation. ''It's either come to an agreement or have the company blown out from under them.''